This invention pertains to a rock crusher impact shoe system which provides a plurality of inserts patterned within the impact shoe to provide substantially increased wear resistance.
Centrifugal impact rock crushers have been known for many years, and in a typical configuration, the input material are typically rocks and are loaded or input through an overhead hopper and then input or fed onto a spinning table which includes one or more impellers or impact shoes mounted thereon. The rocks impact the face of the impact shoes (also referred to as impellers) and are propelled or accelerated radially outward so as to collide with one or more of a plurality of anvils which typically surround the rotating impact shoe table.
There is a tremendous amount of impact, abrasion and substantial wear on the impact shoes and on the surrounding anvils.
FIG. 1 illustrates an exemplary centrifugal impact rock crusher 1, illustrating an input hopper 2, rocks 8 loaded into the input hopper 2 and being fed or metered onto rotating impact shoe table 3.
There are impact shoe supports 4 shown mounted on rotating table 3. Impact shoes 5 are mounted on impact shoe supports 4 on rotating table 3 and provide the hitting or impact surface which hits the rocks 8.
The rocks 8 are typically crushed or broken in two or more locations, the first being as a result of the impact with the impact shoes 5 and the second typically being when the rocks or parts thereof impact the radially outward anvils. The broken rocks 7 impacting the radially outward anvils 6 are shown in FIG. 1 after they are broken. In some cases, impact shoes 5 may make contact more than once with the same rocks or parts of the same rocks before they are propelled radially outward to the anvils 6. There may also be other impacts with rocks bouncing off the anvils and again impacting the impact shoes 5.
FIG. 2 shows the top cutaway view of a rock crusher 40, illustrating rotating impact shoe table 41 with impact shoe supports 42 mounted on rotating impact shoe table 41.
Impact shoes 43 are shown mounted on impact shoe supports 42 and rotating impact shoe table 41. There are other ways to attach impact shoes to the rotating impact shoe table, such as by direct attachment of the impact shoes to the rotating table and/or by placing a separate table piece on the top portion of the impact shoes to further attach and secure the impact shoes in place.
Radially outward from the rotating impact shoe table 41 are a plurality of anvils 44 contained within the centrifugal rock crusher housing and against which the partial or whole rocks may be impacted to break them into the desired pieces, as more fully described with respect to FIG. 1.
Due to the nature of their operation and function, the impact shoes 5 are very high wear components and must regularly be replaced to avoid damaging the impact shoe supports 4.
It is not uncommon on a typical impact shoe table for the table to rotate at approximately seven hundred fifty to two thousand revolutions per minute, or for the ends of the impact shoes to reach speeds up to or exceeding one hundred thirty (130) miles per hour, or greater. Higher speeds further accelerate the wear problem disclosed herein.
While the wear life of impact shoes on a rock crusher depends on many variables, such as the rock being crushed, the speed of the moving parts of the crusher, the desired size of the crushed rock, and other, a typical prior art impact shoe may for example have a useful life of approximately ten (10) operating hours before one or more of the shoes are worn out and must be replaced. It has been found that the impact shoe system disclosed herein, including the pattern or placement of wear-resistant inserts therein, has increased the wear-life of the impact shoes referred to in the example above, to approximately twenty five (25) hours.
There have been prior attempts to increase the wear-life of the impact shoes 5 by changing the composition of the material from which they are made and by placing certain contiguous inserts in the impact shoes to reduce the wear. There has not heretofore been an insert system which extends the life of the impact shoe to the extent this invention does.
FIG. 3 illustrates a typical wear pattern on one prior art impact shoe. The block outline 21 shows an example of the boundaries of an impact shoe 20 before it is used and worn. Impact shoe 20 has a radially inward surface 20a and a radially outward surface 20b. FIG. 3 shows an exemplary wear pattern on an impact shoe, the rocks moving from the inward surface toward the outward surface.
Finding a sufficiently better configuration to increase the wear life of the impact shoes by utilizing internal wear-resistant inserts is limited by certain issues which must be considered in manufacturing the impact shoes. Most of the shoes are cast and during casting it is important that there be sufficient metal surrounding the inserts to locate them in the desired location, and to support, hold or retain the inserts in the desired location. It is therefore difficult to develop a configuration which both increases wear life, and which can be reliably manufactured with inserts secured therein.
FIG. 4 illustrates a prior art impact shoe 30 with an insert 31 located within impact shoe 30. The insert 31 is a continuous piece and has a plurality of extended teeth portions 31a directed toward the face 32 of the impact shoe 30. The insert 31 in the prior art impact shoe 30 illustrated in FIG. 4 is believed to include a ceramic composition insert 31, which may be any one of a number of known compositions, such as ceramic compositions, which are generally known and used in the art. The prior art impact shoe 30 has radially inward side 30a and radially outward side 30b and would be attached to an impact shoe support via a mount portion 33.
The bulk of the wear resistance on the wear insert 31 is believed to be in the base portion and not the teeth 31a. If one were to attempt to place just the base portion 31 at or near the surface 32 of the impact shoe, it would likely not work because there would be insufficient metal holding the insert into place. It is believed that the prior art uses relatively thin fingers 31a in order to position the base portion off the surface 32 of the impact shoe mold allowing the base portion to be secured on all sides with metal during the pouring process.
The distances observed in the prior art shoe for finger width 78 are approximately one-quarter of an inch and for finger spacing 79 is approximately seven-eighths of an inch.
It is therefore an object of this invention to provide an impact shoe for use in a centrifugal impact crusher which increases the wear life beyond that heretofore achieved in the prior art. This invention achieves this objective by providing a plurality of separate or independent or separate wear resistant inserts for introduction and/or location into the impact shoes and provides such plurality in a variety of different patterns or configurations, as discussed and disclosed more fully below. This invention further provides an elongated insert spacing pattern wherein the ratio of the distance between inserts compared to the width of the insert is preferably less than two and one-half to one (2.5:1).
It has been found in comparing the useful or wear life between the prior art impact shoe shown in FIG. 4 and this invention, that the wear insert pattern and configuration provided by this invention outlasts the prior art shown in FIG. 4. This is believed to be because this invention has discovered that providing a plurality of spaced wear inserts provides a longer wear life, while at the same time allowing for sufficient metal flow during manufacturing to secure the inserts within the impact shoes.